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dead time affects many of the instruments used in x-ray astronomy, by producing a strong distortion in power density spectra. this can make it difficult to model the aperiodic variability of the source or look for quasi-periodic oscillations. whereas in some instruments a simple a priori correction for dead-time-affect... | no time for dead time: use the fourier amplitude differences to normalize dead-time-affected periodograms |
magnetars are neutron stars presenting bursts and outbursts of x- and soft-gamma rays that can be understood with the presence of very large magnetic fields. in this setting, nonlinear electrodynamics should be taken into account for a more accurate description of such compact systems. we study that in the context of i... | born-infeld magnetars: larger than classical toroidal magnetic fields and implications for gravitational-wave astronomy |
one of the major and unfortunately unforeseen sources of background for the current generation of x-ray telescopes are few tens to hundreds of kev (soft) protons concentrated by the mirrors. one such telescope is the european space agency's (esa) x-ray multi-mirror mission (xmm-newton). its observing time lost due to b... | prediction and understanding of soft-proton contamination in xmm-newton: a machine learning approach |
we present a flux-resolved x-ray analysis of the dwarf seyfert 1.8 galaxy ngc 4395, based on three archival xmm-newton and one archival nustar observations. the source is known to harbor a low-mass black hole (∼ {10}4{--}{{a}} {few} × {10}5 {m}⊙ ) and shows strong variability in the full x-ray range during these observ... | the nature of the broadband x-ray variability in the dwarf seyfert galaxy ngc 4395 |
the xmm-newton spectral-fit database (xmmfitcat) is a catalogue of spectral fitting results for the source detections within the xmm-newton serendipitous source catalogue with more than 50 net (background-subtracted) counts per detector in the 0.5-10 kev energy band. its most recent version, constructed from the latest... | xmmfitcat: the xmm-newton spectral-fit database |
we present an analysis of high-resolution far-uv archival spectra obtained with the space telescope imaging spectrograph on the hubble space telescope of the star hd 75309, which probes high-velocity shocked gas in the vela supernova remnant (snr). we examine high-velocity features from intrinsically strong absorption ... | observations of multiphase, high-velocity, shocked gas in the vela supernova remnant |
in our earlier study (paper i) of this series, we examined the hemispheric sign preference (hsp) of magnetic helicity flux dh/dt across photospheric surfaces of 4802 samples of 1105 unique active regions (ars) observed during solar cycle 24. here, we investigate any association of the hsp, expressed as a degree of comp... | magnetic helicity flux across solar active region photospheres. ii. association of hemispheric sign preference with flaring activity during solar cycle 24 |
we present new measurements of the vertical density profile of the earth's atmosphere at altitudes between 70 and 200 km, based on earth occultations of the crab nebula observed with the x ray imaging spectrometer onboard suzaku and the hard x ray imager onboard hitomi. x ray spectral variation due to the atmospheric a... | new measurement of the vertical atmospheric density profile from occultations of the crab nebula with x ray astronomy satellites suzaku and hitomi |
the nuclear spectroscopic array (nustar) observed the gamma-ray binary ls 5039 for a second time in order to check for the presence of a periodic signal candidate found in the data from the previous nustar observation. we do not detect the candidate signal in the vicinity of its previously reported frequency, assuming ... | a lack of 9 s periodicity in the follow-up nustar observation of ls 5039 |
inspired by the excess soft x-ray emission recently detected in green pea galaxies, we model the soft x-ray emission (0.5-2.0 kev) of hot gas from star-cluster winds. by combining individual star clusters, we estimate the soft x-ray emission expected from the typically unresolved diffuse hot gas in starburst galaxies, ... | x-ray emission from star-cluster winds in starburst galaxies |
the third catalog of hard fermi large area telescope sources (3fhl) reports the detection of 1556 objects at e > 10 gev. however, 177 sources remain unassociated and 23 are associated with a rosat x-ray detection of unknown origin. pointed x-ray observations were conducted on 30 of these unassociated and unknown sou... | identifying the 3fhl catalog. vi. swift observations of 3fhl unassociated objects with source classification via machine learning |
lobster eye telescopes are ideal monitors to detect x-ray transients because they could observe celestial objects over a wide field of view in the x-ray band. however, images obtained by lobster eye telescopes are modified by their unique point-spread functions, making it hard to design a high-efficiency target detecti... | target detection framework for lobster eye x-ray telescopes with machine-learning algorithms |
we present observations of recurrent active region coronal jets, and derive their thermal and non-thermal properties, by studying the physical properties of the plasma simultaneously at the base footpoint and along the outflow of jets. the sample of analyzed solar jets were observed by sdo-aia in extreme ultraviolet an... | thermal and non-thermal properties of active region recurrent coronal jets |
x-ray missions with microcalorimeter technology will resolve spectral features with unprecedented detail. in this work, we improve the h-like kα energies for elements between 6 ≤ z ≤ 30 for the release version of the spectral simulation code cloudy to match laboratory energies. we update the ionization potential (iion)... | cloudy in the microcalorimeter era: improved energies for kα transitions |
we have specialized astronomical applications for x-ray microcalorimeters with superconducting transition edge sensors (tess) that require exceptionally good tes performance, but which operate in the small-signal regime. we have therefore begun a program to carefully characterize the entire transition surface of tess w... | mapping tes temperature sensitivity and current sensitivity as a function of temperature, current, and magnetic field with iv curve and complex admittance measurements |
the soft x-ray spectrometer (sxs) instrument (mitsuda et al., 2010) [1] on astro-h (takahashi et al., 2010) [2] will use a 3-stage adr (shirron et al., 2012) to cool the microcalorimeter array to 50 mk. in the primary operating mode, two stages of the adr cool the detectors using superfluid helium at ⩽1.20 k as the hea... | thermodynamic performance of the 3-stage adr for the astro-h soft-x-ray spectrometer instrument |
our understanding of the background of the epic/pn camera on board xmm-newton is incomplete. this affects the study of extended sources and can influence the predictions of the expected background of future x-ray missions, such as the advanced telescope for high energy astrophysics (athena). here we provide new results... | analysis of the unconcentrated background of the epic pn camera on board xmm-newton |
astro-h is a japanese x-ray astronomy satellite, scheduled to be launched in fiscal year 2015. the mission includes a soft x-ray spectrometer instrument (sxs), which contains an x-ray micro calorimeter operating at 50 mk by using an adiabatic demagnetization refrigerator (adr). the heat sink of the adr is superfluid li... | flight model performance test results of a helium dewar for the soft x-ray spectrometer onboard astro-h |
future observatories utilizing reflection grating spectrometers for extreme ultraviolet (euv) and soft x-ray (sxr) spectroscopy require high-fidelity gratings with both blazed groove facets and custom groove layouts that are often fanned or feature a slight curvature. while fabrication procedures centering on wet aniso... | extreme ultraviolet and soft x-ray diffraction efficiency of a blazed reflection grating fabricated by thermally activated selective topography equilibration |
most of the baryonic mass in the circumgalactic medium (cgm) of a spiral galaxy is believed to be warm-hot, with temperature around 106 k. the narrow o vi absorption lines probe a somewhat cooler component at $\mathrm{log}\,t({\rm{k}})=5.5$ , but broad o vi absorbers have the potential to probe the hotter cgm. here we ... | probing the hot circumgalactic medium with broad o vi and x-rays |
on 2020 february 24, during their third observing run ("o3"), the laser interferometer gravitational-wave observatory and virgo collaboration detected s200224ca: a candidate gravitational wave (gw) event produced by a binary black hole (bbh) merger. this event was one of the best-localized compact binary coalescences d... | swift multiwavelength follow-up of lvc s200224ca and the implications for binary black hole mergers |
we investigate the mass-velocity dispersion relation (mvdr) in 29 galaxy clusters in the highest x-ray flux galaxy cluster sample (hiflugcs). we measure the spatially resolved, line-of-sight velocity dispersion profiles of these clusters, which we find to be mostly flat at large radii, reminiscent of the rotation curve... | mass-velocity dispersion relation in hiflugcs galaxy clusters |
galactic transient black hole candidate (bhc) maxi j1535-571 was discovered on 2017 september 02 simultaneously by maxi/gsc and swift/bat instruments. it has also been observed by india's first multi-wavelength astronomy-mission satellite astrosat, during the rising phase of its 2017-18 outburst. we make both the spect... | astrosat observation of non-resonant type-c qpos in maxi j1535-571 |
scaling relations are the most powerful astrophysical tools to set constraints on the physical mechanisms of astronomical sources and to infer properties that cannot be accessed directly. we reinvestigate here one of these scaling relations in active galactic nuclei (agns); the so-called x-ray variability plane (or mas... | update on the x-ray variability plane for active galactic nuclei: the role of the obscuration |
in recent years, the cross-spectrum has received considerable attention as a means of characterizing the variability of astronomical sources as a function of wavelength. the cospectrum has only recently been understood as a means of mitigating instrumental effects dependent on temporal frequency in astronomical detecto... | on the statistical properties of cospectra |
x-ray polarimetry has long been considered the `holy grail' of x-ray astronomy. fortunately, after a silence of more than 40 years, the field is now rejuvenating. in fact, an x-ray polarimeter onboard a cube-sat nano-satellite has been recently successfully operated. ixpe, the imaging x-ray polarimetry explorer, will b... | a polarized view of the hot and violent universe |
in this letter, we present the application of a couple of novel deep learning models to the forecast of major solar x-ray flare flux profiles. these models are based on a sequence-to-sequence framework using long short-term memory cell and an attention mechanism. for this, we use geostationary operational environmental... | forecast of major solar x-ray flare flux profiles using novel deep learning models |
aims: using v band photometry of the wings survey, we derive galaxy luminosity functions (lf) in nearby clusters. this sample is complete down to mv = -15.15, and it is homogeneous, thus facilitating the study of an unbiased sample of clusters with different characteristics.methods: we constructed the photometric lf fo... | galaxy luminosity functions in wings clusters |
aims: we probe the radiatively-efficient, hot wind feedback mode in two nearby luminous unobscured (type 1) agn from the close agn reference survey (cars), which show intriguing kpc-scale arc-like features of extended [o iii]ionized gas as mapped with vlt-muse. we aimed to detect hot gas bubbles that would indicate the... | the close agn reference survey (cars). no evidence of galaxy-scale hot outflows in two nearby agn |
the c statistics, also known as the cash statistic, is often used in astronomy for the analysis of low-count poisson data. one of the challenges of the c statistic is that its probability distribution, under the null hypothesis that the data follow a parent model, is not known exactly. such distribution is needed for m... | distribution of the c statistic with applications to the sample mean of poisson data |
cepheids in multiple systems provide information on the outcome of the formation of massive stars. they can also lead to exotic end-stage objects. this study concludes our survey of 70 galactic cepheids using the hubble space telescope (hst) wide field camera 3 (wfc3) with images at two wavelengths to identify companio... | hubble space telescope snapshot survey for resolved companions of galactic cepheids: final results |
we perform x-ray spectral analyses to derive the characteristics (e.g., column density, x-ray luminosity) of ≈10,200 active galactic nuclei (agns) in the xmm-spitzer extragalactic representative volume survey, which was designed to investigate the growth of supermassive black holes across a wide dynamic range of cosmic... | the most obscured agns in the xmm-servs fields |
cadmium-zinc-telluride imager (czti) is one of the five payloads on-board recently launched indian astronomy satellite astrosat. czti is primarily designed for simultaneous hard x-ray imaging and spectroscopy of celestial x-ray sources. it employs the technique of coded mask imaging for measuring spectra in the energy ... | in-orbit performance astrosat czti |
many astrophysical environments involve convective or explosive flows driven by thermonuclear reactions (type ia supernovae, classical novae, x-ray bursts, stellar evolution). simulation codes need to accurately capture the interactions between reactions and hydrodynamics to produce realistic models of these events. fo... | practical effects of integrating temperature with strang split reactions |
the astrophysics division of cea saclay has a long history in the development of cdte based pixelated detection planes for x and gamma-ray astronomy, with time-resolved imaging and spectrometric capabilities. the last generation, named caliste hd, is an all-in-one modular instrument that fulfills requirements for space... | origamix, a cdte-based spectro-imager development for nuclear applications |
all-sky-astrogam is a gamma -ray observatory operating in a broad energy range, 100 kev to a few hundred mev, recently proposed as the ``fast'' (f) mission of the european space agency for a launch in 2028 to an l2 orbit. the scientific payload is composed of a unique gamma -ray imaging monitor for astrophysical transi... | all-sky-astrogam - the mev gamma-ray companion to multimessenger astronomy |
we revealed the detailed structure of a vastly extended hα-emitting nebula (“hα nebula”) surrounding the starburst/merging galaxy ngc 6240 by deep narrow-band imaging observations with the subaru suprime-cam. the extent of the nebula is ∼90 kpc in diameter and the total hα luminosity amounts to lhα ≈ 1.6 × 1042 erg s-1... | giant hα nebula surrounding the starburst merger ngc 6240 |
we present a systematic study of the diffuse hot gas around early-type galaxies (etgs) residing in the virgo cluster, based on archival chandra observations. our representative sample consists of 79 galaxies with low-to-intermediate stellar masses (m* ≈ 109-11 m⊙), a mass range that has not been extensively explored wi... | x-ray constraints on the hot gas content of early-type galaxies in virgo |
we present a brief review of the contemporary understanding of and topical problems in solar flare physics that can be clarified by methods of x-ray and gamma-ray astronomy. the review focuses on several issues, including the conditions and mechanisms of electron acceleration in solar flares, the flare energy distribut... | x-ray and gamma-ray emission from solar flares |
we have been developing event-driven soi pixel detectors, named "xrpix" (x-ray soipixel) based on the silicon-on-insulator (soi) pixel technology, for the future x-ray astronomical satellite with wide band coverage from 0.5 kev to 40 kev. xrpix has event trigger output function at each pixel to acquire a good time reso... | x-ray response evaluation in subpixel level for x-ray soi pixel detectors |
an unusual object, g2, had its pericenter passage around sgr a*, the 4 × 106 m ⊙ supermassive black hole in the galactic center, in summer 2014. several research teams have reported evidence that, following g2's pericenter encounter, the rate of sgr a*'s bright x-ray flares increased significantly. our analysis careful... | no sign of g2's encounter affecting sgr a*'s x-ray flaring rate from chandra observations |
eta carinae’s spectroscopic events (periastron passages) in 2003, 2009, and 2014 differed progressively. he ii λ4687 and nearby n ii multiplet 5 have special significance because they respond to very soft x-rays and the ionizing uv radiation field (euv). hubble space telescope (hst)/stis observations in 2014 show drama... | eta carinae’s 2014.6 spectroscopic event: the extraordinary he ii and n ii features |
introduction: the medium energy x-ray telescope (me) is a collimated x-ray telescope onboard the insight hard x-ray modulation telescope (insight-hxmt) satellite. it has 1728 si-pin pixels readout using 54 low noise application-specific integrated circuits (asics). me covers the energy range of 5-30 kev and has a total... | in-orbit performance of me onboard insight-hxmt in the first 5 years |
we introduce a simple model to explain the time-reversed and stretched residuals in gamma-ray burst (grb) pulse light curves. in this model an impactor wave in an expanding grb jet accelerates from subluminal to superluminal velocities, or decelerates from superluminal to subluminal velocities. the impactor wave intera... | time-reversed gamma-ray burst light-curve characteristics as transitions between subluminal and superluminal motion |
in low earth orbit, there are many cosmic rays composed primarily of high energy protons. these cosmic rays cause surface and bulk radiation effects, resulting in degradation of detector performance. quantitative evaluation of radiation hardness is essential in development of x-ray detectors for astronomical satellites... | proton radiation damage experiment for x-ray soi pixel detectors |
lyα emission is a standard tracer of starburst galaxies at high redshift. however, a number of local lyα emitters (laes) are x-ray sources, suggesting a possible origin of lyα photons other than young, hot stars, and which may be active at much later ages relative to the parent starburst. resolved, nearby laes offer th... | accretion-driven sources in spatially resolved lyα emitters |
core-collapse supernovae (sne) expand into a medium created by winds from the pre-sn progenitor. the sn explosion and resulting shock wave(s) heat up the surrounding plasma, giving rise to thermal x-ray emission, which depends on the density of the emitting material. tracking the variation of the x-ray luminosity over ... | from supernova to remnant: tracking the evolution of the oldest known x-ray supernovae |
hermes pathfinder is an in-orbit demonstration consisting of a constellation of six 3u nano-satellites hosting simple but innovative detectors for the monitoring of cosmic high-energy transients. the main objective of hermes pathfinder is to prove that accurate position of high-energy cosmic transients can be obtained ... | searching for long faint astronomical high energy transients: a data driven approach |
a phase-resolved analysis on the x-ray spectrum of ultraluminous x-ray pulsar (ulxp) ngc 300 ulx-1 is performed with data taken with xmm-newton and nustar on 2016 december 16. in addition to the classical phase-restricting analysis, a method developed in active galactic nuclei studies is newly employed for ulxp. it has... | decomposing the spectrum of ultraluminous x-ray pulsar ngc 300 ulx-1 |
the green river formation preserves an extraordinary archive of terrestrial paleoclimate during the early eocene climatic optimum (eeco; ∼ 53-50 ma), expressing multiple scales of sedimentary cyclicity previously interpreted to reflect annual to milankovitch-scale forcing. here we utilize x-ray fluorescence (xrf) core ... | lacustrine cyclicity in the early eocene green river formation, uinta basin, utah: evidence from x-ray fluorescence core scanning |
we present a detailed weak-lensing and x-ray study of the frontier fields galaxy cluster abell 370, one of the most massive known lenses on the sky, using wide-field br c z' subaru/suprime-cam and chandra x-ray observations. by combining two-dimensional (2d) shear and azimuthally averaged magnification constraints deri... | line-of-sight elongation and hydrostatic mass bias of the frontier fields galaxy cluster abell 370 |
mechanical cryocoolers for space applications are required to have high reliability to achieve long-term operation in orbit. astro-h (hitomi), the 6th japanese x-ray astronomy mission, has a major scientific instrument onboard-the soft x-ray spectrometer (sxs) with several 20k-class two-stage stirling (2st) coolers and... | outgas analysis of mechanical cryocoolers for long lifetime |
we analyzed the unexposed to the sky (outfov) region of the mos2 detector on board xmm-newton covering 15 yr of data amounting to 255 ms. we show convincing evidence that the origin of the unfocused background in xmm-newton is due to energetic protons, electrons, and hard x-ray photons. galactic cosmic rays are the mai... | the origin of the unfocused xmm-newton background, its variability, and lessons learned for athena |
the neutron star interior composition explorer (nicer) records exceptional data on pulsars' energy-dependent x-ray pulse profiles. however, in searching for evidence of pulsations, guillot et al. (2019) introduce a procedure to select an ordered subset of data that maximizes a detection statistic (the h-test). i show t... | selection effects in periodic x-ray data from maximizing detection statistics |
the erosita x-ray telescope, launched in 2019, is predicted to observe roughly 100,000 galaxy clusters. follow-up observations of these clusters from chandra, for example, will be needed to resolve outstanding questions about galaxy cluster physics. deep chandra cluster observations are expensive, and it is unfeasible ... | a machine-learning approach to enhancing erosita observations |
we present a study of the c k-edge using high-resolution letgs chandra spectra of four novae during their super-soft-source (sss) phase. we identified absorption lines due to c ii kα, c iii kα, and c iii kβ resonances. we used these astronomical observations to perform a benchmarking of the atomic data, which involves ... | carbon x-ray absorption in the local ism: fingerprintsin x-ray novae spectra |
the updated program of the future japanese x-ray satellite mission diffuse intergalactic oxygen surveyor (dios), called as super dios, is planned to search for dark baryons in the form of warm-hot intergalactic medium (whim) with high-resolution x-ray spectroscopy. the mission will detect redshifted emission lines from... | super dios: future x-ray spectroscopic mission to search for dark baryons |
an optimal estimate for stokes parameters is derived for the situation in x-ray astronomy where the instrument has a modulation factor that varies significantly with energy but the signals are very weak or mildly polarized. for such sources, the band of analysis may be broadened in order to obtain a significant polariz... | multiband weighting of x-ray polarization data |
the hot halo gas distribution in the inner milky way (mw) contains key fossil records of the past energetic feedback processes in the galactic center. here, we adopt a variety of spherical and disk-like mw halo gas models as initial conditions in a series of simulations to investigate the formation of the fermi bubbles... | probing the halo gas distribution in the inner galaxy with fermi bubble observations |
in the 50 years since the advent of x-ray astronomy there have been many scientific advances due to the development of new experimental techniques for detecting and characterising x-rays. observations of x-ray polarisation have, however, not undergone a similar development. this is a shortcoming since a plethora of ope... | the design and flight performance of the pogolite pathfinder balloon-borne hard x-ray polarimeter |
arches (astronomical resource cross-matching for high energy studies) is a fp7-space funded project whose aim is to provide the international astronomical community with well-characterised multi-wavelength data in the form of spectral energy distributions (seds) for large samples of objects extracted from the 3xmm dr5 ... | the arches project |
suzaku detected an enhancement of the soft x-ray background associated with solar eruptions on 2013 april 14-15. the solar eruptions were accompanied by an m6.5 solar flare and a coronal mass ejection with magnetic flux ropes. the enhanced soft x-ray background showed a slight variation over half a day and then a clear... | suzaku detection of enigmatic geocoronal solar wind charge exchange event associated with coronal mass ejection |
x-ray reflection spectroscopy is potentially a powerful tool to probe the spacetime geometry around astrophysical black holes and test general relativity in the strong field regime. however, precision tests of general relativity are only possible if we employ the correct astrophysical model and if we can limit the syst... | reflection features in the x-ray spectrum of fairall 9 and implications for tests of general relativity |
v341 arae is a 10th-magnitude variable star in the southern hemisphere, discovered over a century ago by henrietta leavitt, but relatively little studied since then. although historically considered to be a cepheid, it is actually blue and coincides with an x-ray source. the star lies near the edge of the large, faint ... | spectroscopy of v341 arae: a nearby nova-like variable inside a bow shock nebula |
we study the contributions to the relativistic fe k α line profile from higher order images (hois) produced by strongly deflected rays from the disc which cross the plunging region, located between the innermost stable circular orbit (isco) radius and the event horizon of a kerr black hole. we investigate the character... | exploring higher order images with fe kα-lines from relativistic discs: black hole spin determination and bias |
we summarize hubble space telescope (hst) uv observations of the weak-lined t tauri star (wtts) pds 70 obtained with the space telescope imaging spectrograph. these observations provide the first far-uv (fuv) and near-uv (nuv) spectra of pds 70. ground-based observations have so far revealed two formative giant planets... | hst uv spectroscopy of the planet-hosting t tauri star pds 70 |
the lack of adequate x-ray observing capability is seriously impeding the progress in understanding the hot phase of circumgalactic medium (cgm), which is predicted to extend to the virial radius of a galaxy or beyond, and thus in acquiring key boundary conditions for studying galaxy evolution. to this end, the hot uni... | mock hubs observations of hot gas with illustristng |
the xmm cluster survey (xcs) have developed a new python module, x-ray: generate and analyse (xga) to provide interactive and automated analyses of x-ray emitting sources observed by the xmm-newton space telescope. xga only requires that a set of cleaned, processed, event lists has been created, and (optionally) that a... | xga: a module for the large-scale scientific exploitation of archival x-ray astronomy data |
an extensive exploration of the model parameter space of axisymmetric early type galaxies (etgs) hosting a central supermassive black hole (smbh) is conducted by means of high-resolution hydrodynamical simulations performed with our code macer. global properties such as (1) total smbh accreted mass, (2) final x-ray lum... | a parameter space exploration of high-resolution numerically evolved early type galaxies including agn feedback and accurate dynamical treatment of stellar orbits |
rotating black holes (bhs) are likely the largest energy reservoirs in the universe as predicted by bh thermodynamics, while cosmic rays (crs) are the most energetic among particles detected on earth. magnetic fields surrounding bhs combined with strong gravity effects, thanks to the spacetime symmetries, turn the bhs ... | constraints on cosmic ray acceleration capabilities of black holes in x-ray binaries and active galactic nuclei |
grailquest (gamma ray astronomy international laboratory for quantum exploration of space-time) is a mission concept based on a constellation (hundreds/thousands) of nano/micro/small-satellites in low (or near) earth orbits. each satellite hosts a non-collimated array of scintillator crystals coupled with silicon drift... | grailquest: hunting for atoms of space and time hidden in the wrinkle of space-time |
one of the holy grails of observational astronomy is to confirm the prediction that black holes in the universe are described by the kerr solution of einstein's field equations of general relativity. this topical collection provides a status report of theoretical and experimental progress towards confirming the "kerr p... | topical collection: testing the kerr spacetime with gravitational-wave and electromagnetic observations |
metals form an essential part of the universe at all scales. without metals we would not exist, and the universe would look completely different. metals are primarily produced via nuclear processes in stars, and spread out through winds or explosions, which pollute the surrounding space. the wanderings of metals in-and... | the voyage of metals in the universe from cosmological to planetary scales: the need for a very high-resolution, high throughput soft x-ray spectrometer |
we have been developing monolithic active pixel sensors, x-ray astronomy soi pixel sensors, xrpixs, based on a silicon-on-insulator (soi) cmos technology as soft x-ray sensors for a future japanese mission, force (focusing on relativistic universe and cosmic evolution). the mission is characterized by broadband (1-80 k... | kyoto's event-driven x-ray astronomy soi pixel sensor for the force mission |
we are developing advanced pixel sensors using silicon-on-insulator (soi) technology. a soi wafer is used; top silicon is used for electric circuit and bottom silicon is used as a sensor. target applications are high-energy physics, x-ray astronomy, material science, non-destructive inspection, medical application and ... | advanced monolithic pixel sensors using soi technology |
erosita aboard the spectrum-roentgen-gamma satellite, successfully launched in july 2019, is the first x-ray astronomical telescope operational at the sun-earth lagrange point l2. a prime scientific goal of erosita is the detection of 100000 clusters of galaxies, which at the fainter luminosity end appears as weak and ... | srg/erosita in-flight background at l2 |
we present a systematic study of gas density perturbations in cool cores of high-mass galaxy clusters. we select 12 relaxed clusters from the cluster lensing and supernova survey with hubble (clash) sample and analyze their cool-core features observed with the chandra x-ray observatory. here, we focus on the x-ray resi... | gas density perturbations in the cool cores of clash galaxy clusters |
we present a comprehensive x-ray spectroscopy and imaging study of supernova remnant w49b using archival xmm-newton observations. the overionization state of the shocked ejecta in w49b is clearly indicated by the radiative recombination continua of si xiv, s xv, and fe xxv, combined with the lyα lines of ca and fe. the... | an xmm-newton x-ray view of supernova remnant w49b: revisiting its recombining plasmas and progenitor type |
nasa's swift satellite has completed ten years of amazing discoveries in time domain astronomy. its primary mission is to chase gamma-ray bursts (grbs), but due to its scheduling flexibility it has subsequently become a prime discovery machine for new types of behavior. the list of major discoveries in grbs and other t... | how swift is redefining time domain astronomy |
since the birth of x-ray astronomy, spectacular advances have been seen in the imaging, spectroscopic and timing studies of the hot and violent x-ray universe, and further leaps forward are expected in the future. on the other hand, polarimetry is very much lagging behind: after the measurements of the crab nebula and ... | esa voyage 2050 white paper: a polarized view of the hot and violent universe |
we propose a novel method to constrain the milky way (mw) mass ${m}_{\mathrm{vir}}$ with its corona temperature observations. for a given corona density profile, one can derive its temperature distribution assuming a generalized equilibrium model with nonthermal pressure support. while the derived temperature profile d... | constraining the milky way mass with its hot gaseous halo |
we have been developing the x-ray silicon-on-insulator (soi) pixel sensor called xrpix for future astrophysical satellites. xrpix is a monolithic active pixel sensor consisting of a high-resistivity si sensor, thin sio2 insulator, and cmos pixel circuits that utilize soi technology. since xrpix is capable of event-driv... | sub-pixel response of double-soi pixel sensors for x-ray astronomy |
we report the second extragalactic pulsar wind nebula (pwn) to be detected in the megaelectronvolt-gigaelectronvolt band by the fermi-lat, located within the large magellanic cloud. the only other known pwn to emit in the fermi band outside of the milky way is n157b, which lies to the west of the newly detected gamma-r... | fermi-lat gamma-ray emission discovered from the composite supernova remnant b0453-685 in the large magellanic cloud |
we present long-term density trends of the earth's upper atmosphere at altitudes between 71 and 116 km, based on atmospheric occultations of the crab nebula observed with x-ray astronomy satellites, asca, rxte, suzaku, nustar, and hitomi. the combination of the five satellites provides a time period of 28 years from 19... | long-term density trend in the mesosphere and lower thermosphere from occultations of the crab nebula with x-ray astronomy satellites |
x‑ray astronomy and ground‑based atomic physics have a long history of fruitful collaboration: sound understanding of the underlying atomic physics is the key to reliable interpretation of the spectra from celestial sources; conversely, astronomical spectra have been used to benchmark and advance atomic physics. this i... | highly charged ions in a new era of high resolution x‑ray astrophysics |
the microchannel x-ray telescope is one of the four instruments of the svom sino-french space mission to observe the afterglow of gamma-ray bursts in the 0.2-10 kev energy range and localize them within 2 arcmin. inside the 9 kg camera, the detection chain consists of a detector assembly equipped with a fully depleted ... | characterization of the focal plane of the microchannel x-ray telescope at the metrology beamline of soleil synchrotron for the space astronomy mission svom |
we report a bright outburst from the high mass x-ray binary lmc x-4 detected by leia (lobster eye imager for astronomy), also known as ep-wxt pathfinder. the detected source position by leia is r.a. = 83.18 deg, dec = -66.36 deg with an uncertainty of 2.2 arcmin (radius, 90% c.l. statistical and systematic), which is 5... | leia detected a bright outburst from lmc x-4 |
we present an x-ray through submillimeter observations of the classical rv tauri (rvb-type) variable u mon, a post-asymptotic giant branch (agb) binary with a circumbinary disk (cbd). our sma observations indicate a cbd diameter of ≲550 au. our xmm-newton observations make u mon the first rv tauri variable detected in ... | multiwavelength observations of the rv tauri variable system u monocerotis: long-term variability phenomena that can be explained by binary interactions with a circumbinary disk |
recent rapid development of deep learning algorithms, which can implicitly capture structures in high-dimensional data, opens a new chapter in astronomical data analysis. we report here a new implementation of deep learning techniques for x-ray analysis. we apply a variational autoencoder (vae) using a deep neural netw... | x-ray study of spatial structures in tycho's supernova remnant using unsupervised deep learning |
the hard x-ray modulation telescope (hxmt) named insight is china's first x-ray astronomical satellite, with the low energy x-ray telescope (le) as one of its main payloads onboard. the detectors of le adopt swept charge device ccd236 using l-shaped transfer electrodes. to measure the time response distribution resulte... | studies on the time response distribution of insight-hxmt/le |
we describe a weak lensing view of the downsizing of star-forming galaxies based on cross-correlating a weak lensing (κ) map with a predicted map constructed from a redshift survey. moderately deep and high-resolution images with subaru/hyper suprime-cam covering the 4 {\deg }2 dls f2 field provide a κ map with 1 arcmi... | a weak lensing view of the downsizing of star-forming galaxies |
we show that the subset of high-energy neutrino events detected by icecube which correlate with the galactic center (within uncertainties of their reconstructed arrival directions) could originate in the collisions of protons accelerated by the sagittarius a* disk dynamo. under very reasonable assumptions on source par... | neutrino lighthouse powered by sagittarius a* disk dynamo |
in the last decades, luminous accreting super-massive black holes have been discovered within the first gyr after the big bang, but their origin is still an unsolved mystery. we discuss our state-of-the-art theoretical knowledge of their formation physics and early growth, and describe the results of dedicated observat... | the dawn of black holes |
time series data mining is an important field of research in the era of 'big data'. next generation astronomical surveys will generate data at unprecedented rates, creating the need for automated methods of data analysis. we propose a method of light-curve characterization that employs a pipeline consisting of a neural... | light-curve fingerprints: an automated approach to the extraction of x-ray variability patterns with feature aggregation - an example application to grs 1915+105 |
in magnetic cataclysmic variables (mcvs), x-ray radiation originates from a shock-heated, multi-temperature plasma in the post-shock region near the white dwarf's surface. these x-rays are modified by a complex distribution of absorbers in the pre-shock region. the presence of photoionized lines and warm absorber featu... | the role of complex ionized absorbers in the soft x-ray spectra of intermediate polars |
highly variable markarian 421 is a bright high-synchrotron energy peaked blazar showing a wide featureless nonthermal spectrum, making it a good candidate for our study of intraday flux and spectral variations over time. we analyze its x-ray observations over 17 yr, taken with the epic-pn instrument, to probe into the ... | x-ray intraday variability of the tev blazar markarian 421 with xmm-newton |
accretion of matter onto the supermassive black holes that live at the heart of most galaxies is one of the most energetic processes in the universe. these active galactic nuclei (agn), and the energy they expel, are believed to play a critical role in how galaxies evolve. despite this, our understanding of how the ene... | the close agn reference survey (cars): data release 1 and beyond |
the exact origins of many type ia supernovae-progenitor scenarios and explosive mechanisms-remain uncertain. in this work, we analyze the global suzaku x-ray spectrum of kepler's supernova remnant (snr) in order to constrain the mass ratios of various ejecta species synthesized during explosion. critically, we account ... | estimating ejecta mass ratios in kepler's supernova remnant: global x-ray spectral analysis including suzaku systematics and emitting volume uncertainties |
the unified model of active galactic nuclei (agns) includes a geometrically thick obscuring medium to explain the differences between type i and type ii agns as an effect of inclination angle. this medium is often referred to as the torus and is thought to be "clumpy" as the line-of-sight column density, n h, has been ... | a simple method for predicting n h variability in active galactic nuclei |
in the framework of the alb3do joint laboratory, cea/irfu and the french company 3d plus are developing a gamma camera with coded mask aperture and compton imaging capabilities: spid-x. it is the last generation gamma camera in a more than two decades history of gamma camera developments at cea/irfu, made commercially ... | the spid-x gamma camera: a miniature gamma ray integral field spectrometer for nuclear industry applications |
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